Heat Exchanger Header Box And Corresponding Heat Exchanger

ABSTRACT

The invention concerns a heat exchanger header box ( 1 ). The header box ( 1 ) includes a flat collecting plate ( 7 ) with openings ( 9 ) for the passage of a plurality of ends ( 5 ) of heat exchange tubes ( 3 ), and a cover ( 15 ) with at least two opposing lateral faces ( 23 ) comprising a peripheral cover base ( 17 ). The cover ( 15 ) closes the header box ( 1 ). According to the invention, the cover ( 15 ) comprises a predefined number of internal tie rods ( 25 ) such that the tie rods ( 25 ) extend respectively between the two opposing side faces ( 23 ) at the level of the cover base ( 17 ), being interposed between two openings ( 9 ) of the collecting plate ( 7 ). The invention further concerns a heat exchanger comprising the header box ( 1 ).

The invention concerns a heat exchanger header box, in particular for a motor vehicle.

The invention also concerns corresponding heat exchangers.

Heat exchangers for use in motor vehicles are already known, for example to cool the engine coolant.

Generally such a heat exchanger comprises a bundle of heat exchange tubes and a header box. This header box comprises at least two parts: a collecting plate holding the ends of the tubes and a cover which comes to be fixed on the collecting plate to close the header box, ensuring the compression of a sealing means.

According to a known solution, the collecting plate comprises a groove or channel intended for placing and positioning of the sealing means. The cover is then positioned on the sealing means and, conventionally, the collecting plate is clamped, for example via clamping plates located on the edge of the collecting plate.

As a variant, flat collecting plates are known with no groove or channel for easily positioning and holding the sealing gasket in place.

The term “flat collecting plate” means that the collecting plate extends over a single flat surface with the exception of lugs, conventionally protruding, to hold the ends of the tubes. In particular on its periphery, the collecting plate has no groove or similar generally used to house the sealing means.

This solution generally requires a cover base to hold the sealing means in position.

Heat exchangers are also known in which the cover, including the cover base, is made of a plastic material.

To be able to assemble the cover and collecting plate, it is important that the cover base is correctly positioned, in particular that it is straight. Otherwise there is a risk that the cover base cannot be inserted in its housing, thus preventing the final assembly of the exchanger.

The purpose of the invention is to guarantee the good insertion of the cover base in the collecting plate.

To this end, the object of the invention is a heat exchanger header box, said header box comprising:

-   -   a flat collecting plate with openings for the passage of a         plurality of ends of heat exchange tubes, and     -   a cover with at least two opposing lateral faces, comprising a         peripheral cover base, closing said header box,

characterized in that said cover comprises a predefined number of internal tie rods such that said tie rods extend respectively between said two opposing lateral faces at the level of said cover base, being interposed between two openings of said collecting plate.

Said header box may also comprise one or more of the following characteristics separately or in combination:

-   -   said cover has a generally substantially arched form and said         tie rods extend between two opposing faces of said arch at the         level of the cover base;     -   said arch has a thickness of substantially between 2 mm and 4         mm;     -   the cover base has a thickness of substantially between 2 mm and         6 mm, preferably between 3 mm and 5 mm;     -   said tie rods are formed integrally with the cover;     -   said tie rods are regularly spaced;     -   the spacing between two tie rods is of the order of 85 mm;     -   said tie rods respectively have a cross section surface area of         the order of 8 mm²;     -   the cover has rounded angles between said opposing faces of the         cover and said tie rods;     -   said rounded angles respectively have a radius of curvature of         the order of 3 mm;     -   said tie rods respectively have an upper free face with         substantially rounded edges.

The invention also concerns a heat exchanger between at least one first fluid and a second fluid, said exchanger comprising a bundle of heat exchange tubes and at least one header box as defined above.

According to one embodiment, said tie rods interposed between two ends of the heat exchange tubes protrude beyond said ends and the protrusion length is of the order of 3 mm.

According to an embodiment variant, said exchanger is an exchanger for mechanical assembly or in another variant, a soldered exchanger.

Further characteristics and advantages of the invention will appear more clearly from reading the description below which is given purely illustratively and non-limitatively, and the attached drawings in which:

FIG. 1 is an exploded simplified view of a header box,

FIG. 2 is a perspective view showing part of a header box and a heat exchange bundle,

FIG. 3 is a side view showing part of the header box and the tube ends of the heat exchange bundle,

FIG. 4 is a cross-sectional view showing schematically part of the cover base with a tie rod according to the first embodiment and the heat exchange bundle, and

FIG. 5 is a schematic cross-sectional view showing part of the cover base with a tie rod according to a second embodiment and the heat exchange bundle.

In these figures, elements which are substantially identical carry the same references.

The invention concerns a heat exchanger for a motor vehicle, for the exchange of heat between at least one first fluid and a second fluid.

Such an exchanger may in particular allow cooling of the engine coolant.

In particular the invention applies to a heat exchanger for mechanical assembly or a soldered heat exchanger.

FIG. 1 shows diagrammatically and in simplified form a heat exchanger header box 1.

A heat exchanger (not shown) generally comprises a bundle 2 formed from a plurality of tubes 3 (see FIGS. 2 to 5) or similar, arranged in one or more rows of tubes 3, one row in the example shown. The tubes 3 can, for example as a variant, be formed respectively by assembly of two plates.

As a variant, such a bundle 2 of tubes 3 may be held in a receiver casing or housing (not shown) which comprises two lateral openings on either side of the bundle 2 of tubes 3, allowing assembly of the bundle 2 with two header boxes 1. These two header boxes 1 allow the inlet and outlet of the first fluid, and the receiver housing generally comprises inlet and outlet openings (not shown) for the second fluid.

The header boxes 1 are mounted symmetrically and can be similar. Naturally as a variant, two different header boxes can be used.

Also the ends 5 of the tubes 3 open into each header box 1 so as to allow circulation of the first fluid in the tubes 3.

With reference again to FIG. 1, a header box 1 comprises:

-   -   a collecting plate 7 comprising openings 9 for the passage of         the ends 5 of the tubes 3, each opening 9 may for example be         edged by a collar 11 which clamps the end 5 of a tube 3,     -   a sealing means such as a sealing gasket 13, and     -   a cover 15 of plastic material with a cover base 17 to close the         header box 1.     -   The collecting plate 7 allows assembly of the tubes 3 with the         header box 1. The tubes 3 can for example be soldered to the         collars 11. This collecting plate 7 is flat i.e. it has no         groove or channel to receive the sealing gasket 13.

The sealing gasket 13 allows the seal between the heat exchange bundle 2 and the header box 1. The sealing gasket 13 (shown diagrammatically and in simplified form) is arranged on the peripheral contour of the collecting plate 7 between the cover base 17 and the collecting plate 7.

The sealing gasket 13 is for example always present between the cover base 17 and the collecting plate 7 such that there is no direct contact between the cover base 17 and the collecting plate 7.

The sealing gasket 13 can thus be arranged so as to be in contact with the tubes 3.

Also the term “cover base” means the lower part of the cover 15 which comes to rest on the sealing gasket 13 and cooperates with the collecting plate 7 to be fixed, conventionally via clamping lugs 19 present on the periphery or circumference of the collecting plate 7 and which fold down over the cover 15 on clamping.

The collecting plate 7 has raised or folded edges 21 which define a housing for the sealing gasket 13 in the same plane as the openings 9, the collecting plate 7 being flat. The clamping lugs 19 are generally provided on these raised edges 21 of the collecting plate 7 to be clamped onto the edges of the cover 15.

Also the cover 15 has a generally substantially arched form with two opposing lateral faces 23. This arch for example has a thickness between 2 mm and 4 mm.

Also the material of the cover 15 including the cover base 17 may contain glass fibers.

The cover base 17 of the cover 15 may have a width for example between 2 mm and 6 mm, preferably substantially between 3 mm and 5 mm.

Therefore there is a significant gain in width of the header box 1 while improving the connection between the cover 15 and the collecting plate 7, in particular the seal.

The cover base 17 can also have a protrusion of height less than the height of the sealing gasket 13 such that there is no direct contact between the cover base 17 and the collecting plate 7. The term “height” of the sealing gasket 13 used here means its height after elastic deformation due to compression of the sealing gasket 13 by the cover base 17.

Also the cover 15 comprises a predefined number of internal tie rods 25. These tie rods 25 are thus arranged inside the cover 15.

More precisely the tie rods 25 are arranged at the level of the cover base 17 and extend respectively between the two opposing lateral faces 23 of the cover 15. The arrangement of these tie rods at the level of the cover base 17 allows the straightness of the cover base 17 to be ensured for its assembly with the collecting plate 7. Naturally these tie rods 25 are also resistant to the pressure of the heat exchanger in operation.

However to prevent damaging the ends 5 of the tubes 3, these tie rods 25 are provided on either side of openings 9 of the collecting plate 7 and hence of the tubes 3 when assembled in the collecting plate 7 (FIGS. 2 and 4).

Each tie rod 25 is thus interposed between two openings 9 of the collecting plate 7, leaving the openings 9 free for the passage of the ends 5 of the tubes 3. There is therefore no obstacle at the level of the tubes 3 of the assembled exchanger.

A tie rod 25 thus has a lower face 25 a oriented towards the collecting plate 7 and an opposing free face 25 b forming the top of the tie rod 25 on the figures shown, and oriented towards the summit of the arch.

The number of tie rods 25 is selected as a function of the length of the cover 15. These tie rods 25 are distributed regularly over the entire length of the cover 15. For example the spacing between two consecutive tie rods 25 is of the order of 85 mm. The Applicant has found that spacing of this order with a margin of either plus or minus 15 mm gives the cover base 17 sufficient straightness for insertion in the collecting plate 7.

To facilitate production, the tie rods 25 can be formed for example by molding integrally with the cover 15.

Also these tie rods 25 respectively have a cross section surface area for example of around 8 mm². This value with an approximate tolerance of plus or minus 25% gives the tie rods a sufficient cross section for them not to break during or after molding of the cover 15 and tie rods 17.

Also as found on FIGS. 2 and 3, the joint between a face 23 of the cover 15 and a tie rod 25 forms a substantially rounded angle 27, for example with a radius of curvature of the order of 3 mm. This rounding also helps to prevent breakage of the tie rod 25.

Also as shown on FIG. 5, it can be provided that the upper free face 25 b of the tie rod 25 has edges of substantially rounded form. The absence of sharp angles facilitates circulation of the first fluid. Also, to limit the production costs of the cover 15, it can be provided that the radii of curvature are not symmetrical.

However once the bundle 2 is assembled with the collecting plate 7, the tie rods 25 interposed between two ends 5 of tubes 3 protrude beyond the ends 5 for example by a length d of around 3 mm. There is therefore a distance d between the free face 25 b of a tie rod 25 and an end 5.

Thus these internal tie rods 25 of the cover, at the level of the cover base 27, prevent the deformation of the cover base and hence guarantee good assembly of the cover 15 with the collecting plate 7 to form the header box 1. 

1. A heat exchanger header box (1) comprising: a flat collecting plate (7) with openings (9) for the passage of a plurality of ends (5) of heat exchange tubes (3), and a cover (15) with at least two opposing lateral faces (23) comprising a peripheral cover base (17), said cover (15) closing said header box (1), wherein said cover (15) comprises a predefined number of internal tie rods (25) such that said tie rods (25) extend respectively between said two opposing lateral faces (23) at the level of said cover base (17), being interposed between two openings (9) of said collecting plate (7).
 2. The header box (1) as claimed in claim 1, wherein said cover (15) has a generally substantially arched form and said tie rods (25) extend between two opposing faces (23) of said arch at the level of said cover base (17).
 3. The header box (1) as claimed in claim 1, wherein said tie rods (25) are formed integrally with said cover (15).
 4. The header box (1) as claimed in claim 3, wherein the spacing between two tie rods (25) is of the order of 85 mm.
 5. The header box (1) as claimed in claim 1, wherein said tie rods (25) respectively have a cross section surface area of the order of 8 mm².
 6. The header box (1) as claimed in claim 1, wherein said cover (15) has rounded angles (27) between said opposing faces (23) of said cover (15) and said tie rods (25).
 7. The header box (1) as claimed in claim 6, wherein said rounded angles (27) respectively have a radius of curvature of the order of 3 mm.
 8. The header box (1) as claimed in claim 1, wherein said tie rods (25) respectively have an upper free face (25 b) with substantially rounded edges.
 9. A heat exchanger between at least one first fluid and a second fluid, said heat exchanger comprising a bundle (2) of heat exchange tubes (3) and at least one header box (1) as claimed in claim
 1. 10. The heat exchanger as claimed in claim 9, wherein said tie rods (25) interposed between two ends (5) of said heat exchange tubes (3) protrude beyond said ends and the protrusion length (d) is of the order of 3 mm.
 11. The header box (1) as claimed in claim 2, wherein said tie rods (25) are formed integrally with said cover (15).
 12. The header box (1) as claimed in claim 11, wherein the spacing between two tie rods (25) is of the order of 85 mm.
 13. The header box (1) as claimed in claim 11, wherein said cover (15) has rounded angles (27) between said opposing faces (23) of said cover (15) and said tie rods (25).
 14. The header box (1) as claimed in claim 2, wherein said cover (15) has rounded angles (27) between said opposing faces (23) of said cover (15) and said tie rods (25).
 15. The header box (1) as claimed in claim 14, wherein said tie rods (25) respectively have an upper free face (25 b) with substantially rounded edges. 